US20140020553A1 - Reciprocating Compressor - Google Patents
Reciprocating Compressor Download PDFInfo
- Publication number
- US20140020553A1 US20140020553A1 US13/937,297 US201313937297A US2014020553A1 US 20140020553 A1 US20140020553 A1 US 20140020553A1 US 201313937297 A US201313937297 A US 201313937297A US 2014020553 A1 US2014020553 A1 US 2014020553A1
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- US
- United States
- Prior art keywords
- piston
- lip ring
- reciprocating compressor
- cylinder
- side portion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000007789 sealing Methods 0.000 claims abstract description 24
- 230000002093 peripheral effect Effects 0.000 description 24
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
- F04B39/0005—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00 adaptations of pistons
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
- F01B15/00—Reciprocating-piston machines or engines with movable cylinders other than provided for in group F01B13/00
- F01B15/02—Reciprocating-piston machines or engines with movable cylinders other than provided for in group F01B13/00 with reciprocating cylinders
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
- F01B9/00—Reciprocating-piston machines or engines characterised by connections between pistons and main shafts and not specific to preceding groups
- F01B9/02—Reciprocating-piston machines or engines characterised by connections between pistons and main shafts and not specific to preceding groups with crankshaft
- F01B9/026—Rigid connections between piston and rod; Oscillating pistons
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
- F04B53/14—Pistons, piston-rods or piston-rod connections
- F04B53/143—Sealing provided on the piston
Definitions
- the present invention relates to a reciprocating compressor.
- a multi-stage compressor which includes a rocking piston provided with a lip ring having an upper sealing portion and a lower sealing portion with the former being more susceptible to elastic deformation than the latter.
- the upper sealing portion of the lip ring disclosed in the above-mentioned patent literature is designed to be easily elastically deformable, so that it tends to be excessively deformed to increase the stress applied to a curved portion of the lip ring. Furthermore, since a large gap is formed between the upper sealing portion of the lip ring and the piston when the piston tilts relative to the cylinder, the lip ring is pressed against the inner peripheral surface of the cylinder causing the stress applied to the curved portion of the lip ring to be further increased. Therefore, the life of the lip ring cannot be lengthened.
- the present invention has been made in view of the above problem, and it is an object of the present invention to provide a reciprocating compressor in which the stress applied to the lip ring is reduced so as to lengthen the life of the lip ring.
- the present invention provides a reciprocating compressor having a piston which compresses air by, while rocking, reciprocatingly moving in a cylinder and a sealing member which is fitted in a groove formed on the piston for sealing between the cylinder and the piston.
- the sealing member has a bottom portion to be fitted in the groove formed on the piston and a side portion provided radially outwardly of the piston; and the side portion includes a bent portion so as to reduce a gap between an upper end portion thereof and the piston.
- the reciprocating compressor according to the present invention can reduce the stress applied to the lip ring used therein and can thereby lengthen the life of the lip ring.
- FIG. 1 is a sectional view of the main body of a reciprocating compressor according to a first embodiment of the present embodiment
- FIG. 2 shows sectional views of a piston and a cylinder according to the first embodiment of the present invention
- FIG. 3A shows a sectional view of a lip ring according to the first embodiment of the present invention
- FIG. 3B shows sectional views of the lip ring according to the first embodiment of the present invention
- FIG. 4 shows sectional views of a lip ring according to a first example case for comparison with the present invention
- FIG. 5 shows sectional views of the lip ring in a rocking state according to the first example case for comparison with the present invention
- FIG. 6 shows sectional views of the lip ring in a rocking state according to a second example case for comparison with the present invention
- FIG. 7 shows sectional views of the lip ring in a rocking state according to the second example case for comparison with the present invention
- FIG. 8 shows a sectional view of a lip ring according to a second embodiment of the present invention.
- FIG. 9 shows a sectional view of a lip ring according to a third embodiment of the present invention.
- FIG. 10 shows a sectional view of a lip ring according to the third embodiment of the present invention.
- a reciprocating compressor according to a first embodiment of the present invention will be described below with reference to FIG. 1 to FIGS. 3A and 3B .
- FIG. 1 is a sectional view of the main body of the reciprocating compressor according to the present embodiment.
- a crankcase 1 of the reciprocating compressor is for forming an internal crank chamber 2 .
- the crankcase 1 is broadly comprised of a cylindrical case section 1 A having a horizontal axis and a cylinder mounting seat 1 B provided on the upper side of the cylindrical case section 1 A.
- a crankshaft 5 is rotatably supported in the crank chamber 2 included in the crankcase 1 .
- the crankshaft 5 is integrally provided with a balance weight 6 .
- the crankshaft 5 is connected to an output shaft 4 of an electric motor 3 and is driven by the electric motor to rotate eccentrically.
- a cylinder 7 is mounted on the cylinder mounting seat 1 B included in the crankcase 1 .
- An inner peripheral surface 7 A of the cylinder 7 serves as a sliding surface for a lip ring 22 being described later.
- a cylinder head 8 is mounted on the top side of the cylinder 7 .
- a discharge chamber 10 for discharging compressed air is formed in the cylinder head 8 .
- a piston rod 14 is, at its base end, rotatably connected to the crankshaft 5 via a bearing 15 .
- a piston 16 provided at an end portion of the piston rod 14 reciprocatingly moves while rocking in the cylinder 7 as shown in FIG. 2 .
- a compression chamber 17 is formed between the piston 16 and a valve seat plate 11 .
- the piston 16 includes a piston main part 18 , a retainer 19 , and a ring receiving groove 21 .
- the piston main part 18 is integrally connected, at an underside central portion thereof, with an end portion of the piston rod 14 .
- the retainer 19 is detachably attached to the upper side of the piston main part 18 so that it can hold the lip ring 22 between itself and the piston main part 18 .
- the lip ring 22 fitted on the outer circumferential side of the piston main part 18 is a sealing member for sealing between the piston 16 and the cylinder 7 so as to prevent air (pressure) leakage from the compression chamber 17 .
- the lip ring 22 is made of, for example, an abrasion-resistant, self-lubricating resin material and has an L-shaped cross-section.
- FIG. 3A is a sectional view of the lip ring 22 without any pressure applied thereto.
- FIG. 3B is a sectional view of the lip ring 22 subjected to a pressure with the piston 16 in a tilted state.
- the lip ring 22 has an annular shape and includes a bottom portion 22 A to be fitted in a groove on the piston 16 and a side portion 22 B formed radially outwardly of the piston 16 .
- the side portion 22 B opens wider upwardly, i.e. toward the compression chamber 17 and slidingly contacts the inner peripheral surface 7 A of the cylinder 7 for sealing between the cylinder 7 and the piston 16 .
- the side portion 22 B of the lip ring 22 has a top end portion 22 B 1 , a base end portion 22 B 2 , and a bent portion 22 B 3 .
- the top end portion 22 B 1 is positioned on the upper end side of the side portion 22 B.
- the base end portion 22 B 2 is positioned on the base end side (lower end side) of the side portion 22 B and extends from the bottom portion 22 A radially outwardly and diagonally upwardly of the piston 16 to be connected to the top end portion 22 B 1 via the bent portion 22 B 3 .
- the bent portion 22 B 3 is positioned between the top end portion 22131 and the base end portion 22 B 2 .
- the side portion 22 B of the lip ring 22 includes plural bends (i.e. a flat surface is bent at plural angles or, in the case of a curved surface, its tangential angle is discontinuously changed).
- An angle ⁇ 1 formed between the top end portion 22 B 1 and the axial direction of the piston 16 is smaller than an angle ⁇ 2 formed between the base end portion 22 B 2 and the axial direction of the piston 16 .
- the gap between the top end portion 22 B 1 of the side portion 22 B and the piston 16 is narrower than in cases where the bent portion 22 B 3 is not formed. This reduces deformation of the lip ring 22 caused when the piston 16 is tilted and pressed against the inner peripheral surface 7 A of the cylinder 7 , so that the stress applied to the lip ring 22 is reduced.
- the magnitude of stress applied to the lip ring 22 is represented by the degree of shading.
- FIG. 3B compared with FIG. 5 , there is almost no dark shading in portions expected to be subjected to stress concentration of the lip ring 22 , indicating that the stress applied to the lip ring 22 is reduced.
- Increasing the angle ⁇ 2 formed between the base end portion 22 B 2 and the axial direction of the piston 16 allows the base end portion 22 B 2 to be tilted more toward the radial direction of the piston 16 so as to cause the top end portion 22 B 1 to contact the inner peripheral surface 7 A of the cylinder 7 at a location farther from the piston 16 .
- a gap S between where the lip ring 22 and the inner peripheral surface 7 A of the cylinder 7 contact each other and the piston 16 can be widened as shown in FIG. 3B , so that the inner peripheral surface 7 A of the cylinder 7 and the piston 16 can be prevented from contacting each other.
- the angle ⁇ 2 formed between the base end portion 22 B 2 and the axial direction of the piston 16 is larger than the rocking angle ⁇ (the angle formed between the axial direction of the piston 16 in a state most tilted relative to the cylinder 7 and the inner peripheral surface 7 A of the cylinder 7 ).
- the base end portion 22 B 2 can move radially outwardly of the piston 16 allowing the contact between the lip ring 22 and the inner peripheral surface 7 A of the cylinder 7 to be radially outside the base end portion 22 B 2 .
- the gap S can be adequately secured between where the lip ring 22 and the inner peripheral surface 7 A of the cylinder 7 contact each other and the piston 16 . In this way, even when the piston 16 is most tilted relative to the cylinder 7 , the inner peripheral surface 7 A of the cylinder 7 and the piston 16 are prevented from contacting each other.
- FIGS. 4 and 5 show enlarged sectional views of the lip ring 22 used in a first example case for comparison with the present embodiment.
- the side portion 22 B of the lip ring 22 has a curved surface of a uniform curvature without any angled bend.
- the side portion 228 having a curved surface of a uniform curvature
- the side portion 22 B of the lip ring 22 is largely deformed as shown in FIG. 5 causing the bottom portion 22 A and the side portion 22 B to be subjected to a large stress.
- the magnitude of stress applied to the lip ring 22 is represented by the degree of shading.
- large portions of the lip ring 22 are darkly shaded indicating stress concentration between the bottom portion 22 A and the side portion 22 B.
- FIGS. 6 and 7 show sectional views of the lip ring 22 used in a second example case for comparison with the present embodiment.
- the lip ring 22 is formed to have an L-shaped section.
- deformation of the lip ring 22 caused by rocking of the piston 16 is smaller than in the first example case, so that the stress applied to the bottom portion 22 A and side portion 22 B is also smaller than in the first example case.
- a gap S between where the lip ring 22 and the inner peripheral surface 7 A of the cylinder 7 contact each other and the piston 16 is adequately secured so as to prevent the inner peripheral surface 7 A of the cylinder 7 and the piston 16 from contacting each other.
- the lower end (bottom) of the lip ring 22 projects outwardly from the piston 16 .
- This increases the outward projection of the lower end (bottom) of the lip ring 22 from the piston 16 when a pressure is applied to the lip ring 22 .
- the stress applied to the bottom portion 22 A of the lip ring 22 when the piston 16 bites into the lower end (bottom) of the lip ring 22 cannot be reduced.
- Thickening the upper end side of the side portion 22 B of the lip ring 22 makes it possible to reduce the stress applied to the lip ring 22 and prevent the inner peripheral surface 7 A of the cylinder 7 and the piston 16 from contacting each other. Doing so, however, excessively increases the rigidity of the upper end side of the side portion 22 B. This makes it less easy for the lip ring 22 to open wider upwardly for enhanced sealing.
- the side portion 22 B of the lip ring 22 has the top end portion 2231 , the base end portion 22 B 2 , and the bent portion 22 B 3 , and the gap between the side portion 22 B and the piston 16 is smaller on the upper end side of the side portion 22 B. In this way, the stress applied to the lip ring 22 is reduced. Also, the gap S between where the lip ring 22 and the inner peripheral surface 7 A of the cylinder 7 contact each other and the piston 16 can be widened, so that the inner peripheral surface 7 A of the cylinder 7 and the piston 16 can be prevented from contacting each other.
- the upper end side of the side portion 22 B of the lip ring 22 does not become too rigid, so that the lip ring 22 can retain adequate sealing performance. This lengthens the life of the lip ring 22 making it possible to provide a reciprocating compressor which can maintain high reliability for a long period of time.
- a reciprocating compressor according to a second embodiment of the present invention will be described with reference to FIG. 8 . Parts identical to those described above in connection with the first embodiment will be denoted by identical reference numerals as used above and their description will be omitted.
- the top end portion 22 B 1 of the side portion 22 B of the lip ring 22 includes plural bends. As shown in FIG. 8 , an angle ⁇ 1 formed between the top end portion 22 B 1 and the axial direction of the piston 16 is smaller than an angle ⁇ 2 also formed between the top end portion 22 B 1 and the axial direction of the piston 16 . Namely, the angle formed on the upper end side of the top end portion 22131 is smaller than the angle formed on the base end side of the top end portion 22 B 1 .
- angles ⁇ 1 and ⁇ 2 formed between the top end portion 22 B 1 and the axial direction of the piston 16 are smaller than an angle ⁇ 3 formed between the base end portion 22 B 2 and the axial direction of the piston 16 .
- the top end portion 22 E 1 extends more closely along the axial direction of the piston 16 on the upper end side than on the base end side. This prevents the gap between the upper end side of the side portion 22 B of the lip ring 22 and the piston 16 from becoming too wide. In this way, the stress applied to the lip ring 22 is further reduced compared with the first embodiment. Also compared with the first embodiment, the side portion 22 B of the lip ring 22 and the inner peripheral surface 7 A of the cylinder 7 contact each other at a location radially more outward from the piston 16 , so that the inner peripheral surface 7 A of the cylinder 7 and the piston 16 can be more securely prevented from contacting each other.
- the top end portion 22 B 1 of the lip ring 22 is shown having two bends, it may include, for example, three or four bends. Increasing the number of bends included in the top end portion 22 B 1 , however, decreases the rigidity of the top end portion 22 B 1 to shorten the life of the lip ring 22 , so that the number of bends included in the top end portion 22 B 1 is preferably in a range of two to four.
- a reciprocating compressor according to a third embodiment of the present invention will be described below with reference to FIGS. 9 and 10 . Parts identical to those described above in connection with the first and second embodiments will be denoted by identical reference numerals as used above and their description will be omitted.
- the lip ring 22 has a curved portion, denoted as R 1 in FIG. 9 , on the inner peripheral surface between the bottom portion 22 A and the side portion 22 B.
- R 1 a curved portion
- the stress applied to the inner peripheral surface between the bottom portion 22 A and the side portion 22 B where stress concentration tends to occur is further reduced.
- providing a curved portion R 2 on the inner peripheral surface of the bent portion 22 B 3 included in the side portion 22 B of the lip ring 22 can further decrease, as compared with the first embodiment, the stress applied to the inner peripheral surface of the bent portion 22 B 3 where stress concentration tends to occur.
Abstract
A reciprocating compressor includes a piston which compresses air by, while rocking, reciprocatingly moving in a cylinder and a sealing member which is fitted in a groove formed on the piston for sealing between the cylinder and the piston. In the reciprocating compressor: the sealing member has a bottom portion to be fitted in the groove formed on the piston and a side portion provided radially outwardly of the piston; and the side portion includes a bent portion so as to reduce a gap between an upper end portion thereof and the piston.
Description
- The present invention relates to a reciprocating compressor.
- A background technique in the present technical field is disclosed, for example, in Japanese Unexamined Patent Application Publication No. 2011-12603. In the patent literature, a multi-stage compressor is disclosed which includes a rocking piston provided with a lip ring having an upper sealing portion and a lower sealing portion with the former being more susceptible to elastic deformation than the latter.
- The upper sealing portion of the lip ring disclosed in the above-mentioned patent literature is designed to be easily elastically deformable, so that it tends to be excessively deformed to increase the stress applied to a curved portion of the lip ring. Furthermore, since a large gap is formed between the upper sealing portion of the lip ring and the piston when the piston tilts relative to the cylinder, the lip ring is pressed against the inner peripheral surface of the cylinder causing the stress applied to the curved portion of the lip ring to be further increased. Therefore, the life of the lip ring cannot be lengthened.
- The present invention has been made in view of the above problem, and it is an object of the present invention to provide a reciprocating compressor in which the stress applied to the lip ring is reduced so as to lengthen the life of the lip ring.
- To address the above problem, the present invention provides a reciprocating compressor having a piston which compresses air by, while rocking, reciprocatingly moving in a cylinder and a sealing member which is fitted in a groove formed on the piston for sealing between the cylinder and the piston. In the reciprocating compressor: the sealing member has a bottom portion to be fitted in the groove formed on the piston and a side portion provided radially outwardly of the piston; and the side portion includes a bent portion so as to reduce a gap between an upper end portion thereof and the piston.
- The reciprocating compressor according to the present invention can reduce the stress applied to the lip ring used therein and can thereby lengthen the life of the lip ring.
-
FIG. 1 is a sectional view of the main body of a reciprocating compressor according to a first embodiment of the present embodiment; -
FIG. 2 shows sectional views of a piston and a cylinder according to the first embodiment of the present invention; -
FIG. 3A shows a sectional view of a lip ring according to the first embodiment of the present invention; -
FIG. 3B shows sectional views of the lip ring according to the first embodiment of the present invention; -
FIG. 4 shows sectional views of a lip ring according to a first example case for comparison with the present invention; -
FIG. 5 shows sectional views of the lip ring in a rocking state according to the first example case for comparison with the present invention; -
FIG. 6 shows sectional views of the lip ring in a rocking state according to a second example case for comparison with the present invention; -
FIG. 7 shows sectional views of the lip ring in a rocking state according to the second example case for comparison with the present invention; -
FIG. 8 shows a sectional view of a lip ring according to a second embodiment of the present invention; -
FIG. 9 shows a sectional view of a lip ring according to a third embodiment of the present invention; and -
FIG. 10 shows a sectional view of a lip ring according to the third embodiment of the present invention. - A reciprocating compressor according to a first embodiment of the present invention will be described below with reference to
FIG. 1 toFIGS. 3A and 3B . -
FIG. 1 is a sectional view of the main body of the reciprocating compressor according to the present embodiment. - A
crankcase 1 of the reciprocating compressor is for forming aninternal crank chamber 2. Thecrankcase 1 is broadly comprised of acylindrical case section 1A having a horizontal axis and acylinder mounting seat 1B provided on the upper side of thecylindrical case section 1A. In thecrank chamber 2 included in thecrankcase 1, acrankshaft 5 is rotatably supported. Thecrankshaft 5 is integrally provided with abalance weight 6. Thecrankshaft 5 is connected to anoutput shaft 4 of anelectric motor 3 and is driven by the electric motor to rotate eccentrically. - A
cylinder 7 is mounted on thecylinder mounting seat 1B included in thecrankcase 1. An innerperipheral surface 7A of thecylinder 7 serves as a sliding surface for alip ring 22 being described later. Acylinder head 8 is mounted on the top side of thecylinder 7. Adischarge chamber 10 for discharging compressed air is formed in thecylinder head 8. - A
piston rod 14 is, at its base end, rotatably connected to thecrankshaft 5 via abearing 15. When thecrankshaft 5 driven by theelectric motor 3 eccentrically rotates, apiston 16 provided at an end portion of thepiston rod 14 reciprocatingly moves while rocking in thecylinder 7 as shown inFIG. 2 . In thecylinder 7, acompression chamber 17 is formed between thepiston 16 and avalve seat plate 11. Thepiston 16 includes a pistonmain part 18, aretainer 19, and a ring receiving groove 21. - The piston
main part 18 is integrally connected, at an underside central portion thereof, with an end portion of thepiston rod 14. Theretainer 19 is detachably attached to the upper side of the pistonmain part 18 so that it can hold thelip ring 22 between itself and the pistonmain part 18. - The
lip ring 22 fitted on the outer circumferential side of the pistonmain part 18 is a sealing member for sealing between thepiston 16 and thecylinder 7 so as to prevent air (pressure) leakage from thecompression chamber 17. Thelip ring 22 is made of, for example, an abrasion-resistant, self-lubricating resin material and has an L-shaped cross-section. - The
lip ring 22 of the present embodiment will be described with reference toFIGS. 3A and 3B .FIG. 3A is a sectional view of thelip ring 22 without any pressure applied thereto.FIG. 3B is a sectional view of thelip ring 22 subjected to a pressure with thepiston 16 in a tilted state. Thelip ring 22 has an annular shape and includes abottom portion 22A to be fitted in a groove on thepiston 16 and aside portion 22B formed radially outwardly of thepiston 16. Theside portion 22B opens wider upwardly, i.e. toward thecompression chamber 17 and slidingly contacts the innerperipheral surface 7A of thecylinder 7 for sealing between thecylinder 7 and thepiston 16. - According to the present embodiment, the
side portion 22B of thelip ring 22 has a top end portion 22B1, a base end portion 22B2, and a bent portion 22B3. The top end portion 22B1 is positioned on the upper end side of theside portion 22B. The base end portion 22B2 is positioned on the base end side (lower end side) of theside portion 22B and extends from thebottom portion 22A radially outwardly and diagonally upwardly of thepiston 16 to be connected to the top end portion 22B1 via the bent portion 22B3. The bent portion 22B3 is positioned between the top end portion 22131 and the base end portion 22B2. Theside portion 22B of thelip ring 22 includes plural bends (i.e. a flat surface is bent at plural angles or, in the case of a curved surface, its tangential angle is discontinuously changed). - An angle θ1 formed between the top end portion 22B1 and the axial direction of the
piston 16 is smaller than an angle θ2 formed between the base end portion 22B2 and the axial direction of thepiston 16. Namely, with the bent portion 22B3 formed, the gap between the top end portion 22B1 of theside portion 22B and thepiston 16 is narrower than in cases where the bent portion 22B3 is not formed. This reduces deformation of thelip ring 22 caused when thepiston 16 is tilted and pressed against the innerperipheral surface 7A of thecylinder 7, so that the stress applied to thelip ring 22 is reduced. InFIG. 3B , the magnitude of stress applied to thelip ring 22 is represented by the degree of shading. InFIG. 3B , compared withFIG. 5 , there is almost no dark shading in portions expected to be subjected to stress concentration of thelip ring 22, indicating that the stress applied to thelip ring 22 is reduced. - Increasing the angle θ2 formed between the base end portion 22B2 and the axial direction of the
piston 16 allows the base end portion 22B2 to be tilted more toward the radial direction of thepiston 16 so as to cause the top end portion 22B1 to contact the innerperipheral surface 7A of thecylinder 7 at a location farther from thepiston 16. In this way, a gap S between where thelip ring 22 and the innerperipheral surface 7A of thecylinder 7 contact each other and thepiston 16 can be widened as shown inFIG. 3B , so that the innerperipheral surface 7A of thecylinder 7 and thepiston 16 can be prevented from contacting each other. - The angle θ2 formed between the base end portion 22B2 and the axial direction of the
piston 16 is larger than the rocking angle θ (the angle formed between the axial direction of thepiston 16 in a state most tilted relative to thecylinder 7 and the innerperipheral surface 7A of the cylinder 7). In this way, even when thepiston 16 is most tilted relative to thecylinder 7, the base end portion 22B2 can move radially outwardly of thepiston 16 allowing the contact between thelip ring 22 and the innerperipheral surface 7A of thecylinder 7 to be radially outside the base end portion 22B2. Thus, the gap S can be adequately secured between where thelip ring 22 and the innerperipheral surface 7A of thecylinder 7 contact each other and thepiston 16. In this way, even when thepiston 16 is most tilted relative to thecylinder 7, the innerperipheral surface 7A of thecylinder 7 and thepiston 16 are prevented from contacting each other. - As shown in
FIG. 3A , when thelip ring 22 is subjected to no pressure, the lower end (bottom) of thelip ring 22 does not project outwardly from thepiston 16. This reduces the outward projection of the lower end (bottom) of thelip ring 22 from thepiston 16 in a state with a pressure applied to thelip ring 22. In this arrangement, the stress generated when thepiston 16 bites into the lower end (bottom) of thelip ring 22 is reduced. -
FIGS. 4 and 5 show enlarged sectional views of thelip ring 22 used in a first example case for comparison with the present embodiment. In the first example case for comparison, theside portion 22B of thelip ring 22 has a curved surface of a uniform curvature without any angled bend. With the side portion 228 having a curved surface of a uniform curvature, when thepiston 16 rocks, theside portion 22B of thelip ring 22 is largely deformed as shown inFIG. 5 causing thebottom portion 22A and theside portion 22B to be subjected to a large stress. InFIG. 5 , the magnitude of stress applied to thelip ring 22 is represented by the degree of shading. InFIG. 5 compared withFIG. 3B , large portions of thelip ring 22 are darkly shaded indicating stress concentration between thebottom portion 22A and theside portion 22B. -
FIGS. 6 and 7 show sectional views of thelip ring 22 used in a second example case for comparison with the present embodiment. In the second example case, thelip ring 22 is formed to have an L-shaped section. In the second example case with theside portion 22B being flat-surfaced, deformation of thelip ring 22 caused by rocking of thepiston 16 is smaller than in the first example case, so that the stress applied to thebottom portion 22A andside portion 22B is also smaller than in the first example case. - Referring to
FIG. 6 , a gap S between where thelip ring 22 and the innerperipheral surface 7A of thecylinder 7 contact each other and thepiston 16 is adequately secured so as to prevent the innerperipheral surface 7A of thecylinder 7 and thepiston 16 from contacting each other. In this case, when thelip ring 22 is subjected to no pressure, the lower end (bottom) of thelip ring 22 projects outwardly from thepiston 16. This increases the outward projection of the lower end (bottom) of thelip ring 22 from thepiston 16 when a pressure is applied to thelip ring 22. In this arrangement, the stress applied to thebottom portion 22A of thelip ring 22 when thepiston 16 bites into the lower end (bottom) of thelip ring 22 cannot be reduced. - Referring to
FIG. 7 , when thelip ring 22 is subjected to no pressure, the lower end (bottom) of thelip ring 22 does not project outwardly from thepiston 16. This is to reduce the stress generated when thepiston 16 bites into the lower end (bottom) of thelip ring 22. In this case, however, a gap S between where thelip ring 22 and the innerperipheral surface 7A of thecylinder 7 contact each other and thepiston 16 cannot be adequately secured. - Thickening the upper end side of the
side portion 22B of thelip ring 22 makes it possible to reduce the stress applied to thelip ring 22 and prevent the innerperipheral surface 7A of thecylinder 7 and thepiston 16 from contacting each other. Doing so, however, excessively increases the rigidity of the upper end side of theside portion 22B. This makes it less easy for thelip ring 22 to open wider upwardly for enhanced sealing. - As described above, according to the present embodiment, the
side portion 22B of thelip ring 22 has the top end portion 2231, the base end portion 22B2, and the bent portion 22B3, and the gap between theside portion 22B and thepiston 16 is smaller on the upper end side of theside portion 22B. In this way, the stress applied to thelip ring 22 is reduced. Also, the gap S between where thelip ring 22 and the innerperipheral surface 7A of thecylinder 7 contact each other and thepiston 16 can be widened, so that the innerperipheral surface 7A of thecylinder 7 and thepiston 16 can be prevented from contacting each other. Furthermore, in this arrangement, the upper end side of theside portion 22B of thelip ring 22 does not become too rigid, so that thelip ring 22 can retain adequate sealing performance. This lengthens the life of thelip ring 22 making it possible to provide a reciprocating compressor which can maintain high reliability for a long period of time. - A reciprocating compressor according to a second embodiment of the present invention will be described with reference to
FIG. 8 . Parts identical to those described above in connection with the first embodiment will be denoted by identical reference numerals as used above and their description will be omitted. - In the second embodiment, the top end portion 22B1 of the
side portion 22B of thelip ring 22 includes plural bends. As shown inFIG. 8 , an angle θ1 formed between the top end portion 22B1 and the axial direction of thepiston 16 is smaller than an angle θ2 also formed between the top end portion 22B1 and the axial direction of thepiston 16. Namely, the angle formed on the upper end side of the top end portion 22131 is smaller than the angle formed on the base end side of the top end portion 22B1. In the second embodiment, too, like in the first embodiment, the angles θ1 and θ2 formed between the top end portion 22B1 and the axial direction of thepiston 16 are smaller than an angle θ3 formed between the base end portion 22B2 and the axial direction of thepiston 16. - In the present embodiment, with the top end portion 22B1 including plural bends, the top end portion 22E1 extends more closely along the axial direction of the
piston 16 on the upper end side than on the base end side. This prevents the gap between the upper end side of theside portion 22B of thelip ring 22 and thepiston 16 from becoming too wide. In this way, the stress applied to thelip ring 22 is further reduced compared with the first embodiment. Also compared with the first embodiment, theside portion 22B of thelip ring 22 and the innerperipheral surface 7A of thecylinder 7 contact each other at a location radially more outward from thepiston 16, so that the innerperipheral surface 7A of thecylinder 7 and thepiston 16 can be more securely prevented from contacting each other. - Even though, in
FIG. 8 , the top end portion 22B1 of thelip ring 22 is shown having two bends, it may include, for example, three or four bends. Increasing the number of bends included in the top end portion 22B1, however, decreases the rigidity of the top end portion 22B1 to shorten the life of thelip ring 22, so that the number of bends included in the top end portion 22B1 is preferably in a range of two to four. - A reciprocating compressor according to a third embodiment of the present invention will be described below with reference to
FIGS. 9 and 10 . Parts identical to those described above in connection with the first and second embodiments will be denoted by identical reference numerals as used above and their description will be omitted. - In the third embodiment, the
lip ring 22 has a curved portion, denoted as R1 inFIG. 9 , on the inner peripheral surface between thebottom portion 22A and theside portion 22B. Compared with the first embodiment, in the third embodiment with the curved portion R1 provided on the inner peripheral surface between thebottom portion 22A and theside portion 22B, the stress applied to the inner peripheral surface between thebottom portion 22A and theside portion 22B where stress concentration tends to occur is further reduced. - Also, as shown in
FIG. 10 , providing a curved portion R2 on the inner peripheral surface of the bent portion 22B3 included in theside portion 22B of thelip ring 22 can further decrease, as compared with the first embodiment, the stress applied to the inner peripheral surface of the bent portion 22B3 where stress concentration tends to occur. - The foregoing embodiments each represent a mere example of application of the present invention, and they do not define the technical scope of the present invention. The present invention can be applied in various manners without departing from the technical concept and main features thereof. The first to the third embodiments described above may also be combined in implementing the present invention.
Claims (11)
1. A reciprocating compressor, comprising:
a piston which compresses air by, while rocking, reciprocatingly moving in a cylinder; and
a sealing member which is fitted in a groove formed on the piston for sealing between the cylinder and the piston,
wherein the sealing member has a bottom portion to be fitted in the groove formed on the piston and a side portion provided radially outwardly of the piston, and
wherein the side portion includes a bent portion so as to reduce a gap between an upper end portion thereof and the piston.
2. The reciprocating compressor according to claim 1 , wherein an angle formed between a base end side of the side portion and the axial direction of the piston is larger than a rocking angle of the piston.
3. The reciprocating compressor according to claim 1 , wherein the bottom portion of the sealing member is prevented from moving outwardly of the groove formed on the piston.
4. The reciprocating compressor according to claim 1 , wherein the side portion includes a plurality of bends.
5. The reciprocating compressor according to claim 1 , wherein the bent portion of the sealing member has a curved inner side surface.
6. The reciprocating compressor according to claim 1 , wherein an inner side surface between the side portion and the bottom portion is curved.
7. A reciprocating compressor comprising:
a piston which compresses air by, while rocking, reciprocatingly moving in a cylinder; and
a sealing member which is fitted in a groove formed on the piston for sealing between the cylinder and the piston,
wherein the sealing member has a bottom portion to be fitted in the groove formed on the piston and a side portion provided radially outwardly of the piston, and
wherein the side portion includes a plurality of bends causing a first angle formed between an upper end side of the side portion and the axial direction of the piston to be smaller than a second angle formed between a base end side of the side portion and the axial direction of the piston.
8. The reciprocating compressor according to claim 7 , wherein the second angle formed between the base end side of the side portion and the axial direction of the piston is larger than a rocking angle of the piston.
9. The reciprocating compressor according to claim 7 , wherein the bottom portion of the sealing member is prevented from moving outwardly of the groove formed on the piston.
10. The reciprocating compressor according to claim 7 , wherein the plurality of bends have a curved inner side surface.
11. The reciprocating compressor according to claim 7 , wherein an inner side surface between the side portion and the bottom portion is curved.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2012161133A JP5993644B2 (en) | 2012-07-20 | 2012-07-20 | Reciprocating compressor |
JP2012-161133 | 2012-07-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20140020553A1 true US20140020553A1 (en) | 2014-01-23 |
Family
ID=49945460
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/937,297 Abandoned US20140020553A1 (en) | 2012-07-20 | 2013-07-09 | Reciprocating Compressor |
Country Status (3)
Country | Link |
---|---|
US (1) | US20140020553A1 (en) |
JP (1) | JP5993644B2 (en) |
CN (1) | CN103573611B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20220106950A1 (en) * | 2019-10-01 | 2022-04-07 | Hitachi Industrial Equipment Systems Co., Ltd. | Compressor |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106321419A (en) * | 2016-10-10 | 2017-01-11 | 国家海洋局天津海水淡化与综合利用研究所 | Novel self-seal type piston |
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Also Published As
Publication number | Publication date |
---|---|
CN103573611B (en) | 2015-11-25 |
JP5993644B2 (en) | 2016-09-14 |
JP2014020309A (en) | 2014-02-03 |
CN103573611A (en) | 2014-02-12 |
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AS | Assignment |
Owner name: HITACHI INDUSTRIAL EQUIPMENT SYSTEMS CO., LTD., JA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HARASHIMA, TOSHIKAZU;IWANO, KIMINORI;SADAKATA, KOSUKE;REEL/FRAME:031027/0535 Effective date: 20130613 |
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